Method and apparatus for the recording of properties on elongate bodies

Abstract

The invention relates to a method and apparatus in which an elongated body (1) such as a yarn, a roving or a band, is measured continuously by means of a simple cost-effective sensor (5). A further, more complicated sensor (8) which works more accurately but more slowly is triggered by the simpler sensor if the latter indicates special events. These events are then stored by the complicated sensor and are subsequently analyzed accurately in a greater amount of time. The entire time span occurring between two special events can be utilized for this analysis.

What is claimed is: 
     
       1. Device for sensing and recording a characteristic property of an elongate body which is moved in the longitudinal direction, said device comprising: a first sensor for sensing and recording first data indicative of said characteristic property to a first degree of accuracy sufficient for routine examination of the elongate body and for generating a trigger signal when said first data indicate an exceptional condition of said characteristic property; and   a second sensor responsive to said first sensor for sensing and recording second data indicative of said characteristic property to a second degree of accuracy greater than said first degree of accuracy when triggered by said trigger signal.   
     
     
       2. Device according to claim 1, wherein the first sensor works continuously and employs a first measuring technique, whilst the second sensor works discontinuously and employs a second measuring technique different from said first measuring technique. 
     
     
       3. Device according to claim 1, wherein the second sensor is designed and arranged for recording and processing images. 
     
     
       4. Device according to claim 1, wherein the second sensor is located downstream of the first sensor in the direction of movement of the body. 
     
     
       5. Device according to claim 1, further comprising a data storage device connected to the second sensor for storing said data. 
     
     
       6. Device according to claim 1, second sensor is located upstream of the first sensor in the direction of movement of the body and further comprising a data storage device connected to said second sensor for time-restricted storage of said second data. 
     
     
       7. Device according to claim 1, further comprising a signal conditioning element connected to said second sensor for conditioning of signals generated by said second sensor. 
     
     
       8. Method for recording a characteristic property of an elongate body which is moved in the longitudinal direction, comprising the steps of: continuously sensing and recording first data indicative of said property of the body using a first measuring technique; and   discontinuously sensing and recording second data indicative of said property using a second measuring technique different from said first measuring technique.   
     
     
       9. Method according to claim 8, wherein said first and second measuring techniques are such that said second data are more accurate than said first data.